Updated: Jul 31
The betta fish (Betta splendens) is one the most common aquarium fish, and a great species for the beginner aquarist. The myth of bettas being able to live out their lives in a bowl or small non-filtered aquarium came about because of an interesting adaptation the betta processes.
In the rice paddies of Southeast Asia, the wild betta goes about it's betta business; defending his territory, looking for mates, blowing bubble nests, and hunting for small insects and invertebrates. During the wet season, October to June, the betta has ample habitat and plenty of room to thrive. During the dry season, July to September, if it does rain, it is only for an hour in the afternoon (Solace Global 2018). The lack of rain dries up the bettas' habitat and limits it's range. Sometimes, it gets so dry bettas are reduced to surviving in a small mud puddle for up to weeks on end. These puddles are extremely low in oxygen and can become so small the betta is out of water for a short period of time. To overcome this hostile condition, bettas and other anabantoid fish evolved a labyrinth organ. This modified branchial gill arch is a many-folded organ that can take in atmospheric oxygen and distribute it to the bloodstream, much like our lungs (Pinter 1986). This allows the betta to survive long enough to find a more hospitable environment or until it rains again.
Obviously, lying in a drying up, dirty, low-oxygen puddle, ready to die at a moments notice is no way to live. Just because the betta evolved to survive in this extreme for a short period, should not mean we subject it to this environment for its entire life. Besides the ethical implications of such treatment, the betta's health, color and activity will increase profoundly when kept in the proper environment.
So what is the proper environment for a betta? I'm not suggesting you take out a loan and build a pond for your betta, (although betta ponds do exist). Really all you need is a properly sized tank, good filtration, a heater, live plants, and a decent light, just like for any other freshwater fish.
The betta's natural territory is generally considered to be about 3 feet square. As they are surface dwelling fish, that is where they spend most of their time, so depth is not as important as length and width. Getting as close to this 3 square foot measurement as possible is the goal even if we include the third dimension and allow for 3 feet cubed. This comes out to about 20 gallons. Your betta's home should definitely be no less than 10 gallons. This size of tank makes a great desktop aquarium, and can even fit on your bookshelf, provided your shelf can hold at least 90 pounds. 10 to 20 gallons is ideal because it is enough water to buffer changes in pH, temperature, and nutrient levels, but is not so large it becomes a hassle to clean for the beginner. Anything smaller than 10 gallons and you will find limited filtration, lighting and heating options.
Good filtration can come in the form of a simple hang-on-back filter rated for 10-20 gallons, or even an air bubbler attached to an internal sponge filter. They even make internal filters for nano-tanks that are quiet and easy to hide.
Bettas are tropical fish and their ideal temperature range is between 75 and 80 degrees Fahrenheit. You can pick up a small automatic heater that keeps the water at 78 exactly, or invest in a controlled thermostat heater, allowing you to adjust the temperature manually. This is better if you have a draft or keep your home cooler than average.
Bettas love plants. They will sleep on large leaves and their natural environment includes many dense species creating an underwater jungle of sorts. In addition, live plants will benefit the health of your aquarium by absorbing excess nutrients such as harmful phosphates and nitrates that can become toxic and cause nuisance algae growth.
Finally, a full spectrum LED light will help your plants grow, but also reveal your betta's beautiful and vibrant colors.
This article has only touched the surface of owning a betta fish. There is much more to discover such as diet, behavior, ideal water chemistry, breeding and even betta sororities. I simply wanted to start by making the case for housing your betta in an appropriately sized aquarium. Just because they can survive in a bowl does not mean they will thrive there.
Solace Global. 2018. South Asia 2018 Monsoon Season Report.
Pinter, H. (1986). Labyrinth Fish. Barron's Educational Series, Inc.